Why Do External Thermal Insulation Materials Always Cause Fires?


Release Time:

2023-02-06

At present, the building external wall insulation material is one of the important items for sampling interior finish materials, which is closely related to their frequent occurrence of fire accidents. For example, the fire in CCTV building originated from the use of non-flammable organic insulation materials. These materials produce a large amount of smoke and toxic gases due to incomplete combustion and pyrolysis during fires, and most people in fire accidents may suffocate by inhaling these smoke and toxic gases. Therefore, the fire risk caused by building external wall insulation material is very high, which is easy to cause major casualties. And based on work experience, the author discusses the causes for the fire and preventive measures. Firstly, the industry standards are not sound, and the product quality is uneven. At present, the production and use of external insulation materials are chaotic. And the organic insulation materials currently used in the building field mainly include polystyrene board (EPS), extruded polystyrene board (XPS), and polyurethane (PU), whose greatest strengths are that they are lightweight, good in insulation and thermal insulation. And their biggest weaknesses include poor fire safety, easy aging and flammable. The first two are widely used due to their low prices, while the latter is slightly superior in terms of thermal conductivity, construction performance, and combustion performance. The industry standards for external insulation materials are not yet sound, and some manufacturers have loopholes in management. The external insulation materials produced cannot meet the design requirements of building fire protection, and the fire resistance grade and limit cannot meet the national standards. After the product is put on the market, congenital safety risks are posed for building fire accidents. Secondly, the construction cycle is long and there are numerous hidden dangers at the construction site. For the construction industry, energy conservation and insulation is the national policy, and wall insulation is an important means to realize building energy conservation, thus building insulation materials are widely used. In reality, the construction period of high-rise buildings, large-scale stadiums and other buildings is generally two to three years, during which various construction processes alternate with each other and are inconvenient to manage. Some management personnel neglect the investigation and rectification of on-site fire hazards and the setting of temporary fire water, and focus all their energy on catching up with the construction period and squeezing costs.

At present, the building external wall insulation material is one of the important items for sampling interior finish materials, which is closely related to their frequent occurrence of fire accidents. For example, the fire in CCTV building originated from the use of non-flammable organic insulation materials. These materials produce a large amount of smoke and toxic gases due to incomplete combustion and pyrolysis during fires, and most people in fire accidents may suffocate by inhaling these smoke and toxic gases. Therefore, the fire risk caused by building external wall insulation material is very high, which is easy to cause major casualties. And based on work experience, the author discusses the causes for the fire and preventive measures. Firstly, the industry standards are not sound, and the product quality is uneven. At present, the production and use of external insulation materials are chaotic. And the organic insulation materials currently used in the building field mainly include polystyrene board (EPS), extruded polystyrene board (XPS), and polyurethane (PU), whose greatest strengths are that they are lightweight, good in insulation and thermal insulation. And their biggest weaknesses include poor fire safety, easy aging and flammable. The first two are widely used due to their low prices, while the latter is slightly superior in terms of thermal conductivity, construction performance, and combustion performance. The industry standards for external insulation materials are not yet sound, and some manufacturers have loopholes in management. The external insulation materials produced cannot meet the design requirements of building fire protection, and the fire resistance grade and limit cannot meet the national standards. After the product is put on the market, congenital safety risks are posed for building fire accidents. Secondly, the construction cycle is long and there are numerous hidden dangers at the construction site. For the construction industry, energy conservation and insulation is the national policy, and wall insulation is an important means to realize building energy conservation, thus building insulation materials are widely used. In reality, the construction period of high-rise buildings, large-scale stadiums and other buildings is generally two to three years, during which various construction processes alternate with each other and are inconvenient to manage. Some management personnel neglect the investigation and rectification of on-site fire hazards and the setting of temporary fire water, and focus all their energy on catching up with the construction period and squeezing costs. 

 

During the construction period of two to three years, there are many combustible materials on site, which makes it difficult to discover fire hazards in a timely manner. The external wall insulation material has the characteristics of extremely fast spreading, hidden combustion, and difficulty in controlling once a fire breaks out, which can easily cause significant personnel and property losses due to the carelessness of field personnel. Thirdly, the cost of qualified materials is high, and the construction unit is shoddy. Ji Guangqi, a researcher at the China Academy of Building Research Institute of Building Fire Research, once said in a program on CCTV titled “Flammability of Building Insulation Materials Raising Concerns”: “In fact, many insulation materials nowadays, polystyrene or hard foam insulation paper, are not up to standard, that is, they are B3 materials, and combustible. They can easily catch fire and cause fires. Taking extruded boards as an example, those that meet fire protection standards are more than twice as expensive as the combustible extruded boards.” At present, insulation materials are divided into four grades: A (non-combustible), B1 (fire-retardant), B2 (flammable), and B3 (combustible), and two categories: Inorganic insulation materials and organic insulation materials. The former has the characteristic of non-combustible, but poor insulation effect, occupying only about 20% of the market share. The latter has the characteristic of good insulation effect, but easy to burn, occupying 80% of the market share. Therefore, it is necessary to add a certain amount of flame retardant to the material to meet the standard, however flame retardants are expensive, and many businesses, in pursuit of maximizing profits, add less flame retardants or none at all. Some construction units intentionally purchase inferior insulation materials, passing them off as shoddy, saving costs, and with inadequate fire supervision, it is easy to muddle through. Secondly, one of the fire prevention countermeasures of external insulation materials is to improve the public’s awareness on external insulation materials and make scientific prevention. From a practical perspective, it is impossible for people to completely deny the use of some external insulation materials in buildings just because they are flammable. In fact, the key lies in how to use them safely and in a standardized manner. If the use of external wall insulation materials is standardized, the supervision on external wall insulation materials is intensified, the fire extinguishing measures are complete, and the safety awareness is improved, most fires caused by external wall insulation materials can be prevented. At present, a large number of organic external insulation materials are used in newly built buildings in China, such as expanded polystyrene board, extruded polystyrene board, and foam polyurethane. Their insulation performance is better than most of the inorganic materials, and is the mainstream building insulation materials. 

 

But in terms of material performance, they have a low ignition point and are flammable. If a large amount of these combustible insulation materials is wrapped on the building, it will inevitably leave a fire hazard. Therefore, the departments concerned must strengthen the fire control management of such buildings and raise public scientific awareness of these materials to make scientific prevention. The second countermeasure is to strictly manage the construction site and eliminate safety hazards. A domestic statistical report showed that about 25% of fires involving building insulation materials occur during the stacking of insulation materials, 65% occur during the laying of insulation materials, and less than 10% occur during the use of buildings. It can be seen that the construction process of building wall insulation is a high-risk period for fire accidents. Regulatory authorities shall strengthen the standardized management of the manufacturers, construction enterprises and markets of building external wall insulation material, carry out the certification of wall insulation systems, and introduce licenses, insurance and other systems to improve the safety of building wall insulation. When carrying out fire supervision and inspection, the fire department shall transmit the awareness of fire prevention to the management personnel at the construction site, and also require that each working face shall be ensured to have a fire water supply at the construction site, so as to carry out self-rescue in case of fire. Only strict construction site management can eliminate fire safety hazards to the maximum extent. The third countermeasure is to update and improve various types of firefighting and rescue equipment, and enhance the ability to tackle difficulties. At present, the speed of fire equipment “growing taller” in China is far from keeping up with the speed of building “growing taller”. 

 

But in terms of material performance, they have a low ignition point and are flammable. If a large amount of these combustible insulation materials is wrapped on the building, it will inevitably leave a fire hazard. Therefore, the departments concerned must strengthen the fire control management of such buildings and raise public scientific awareness of these materials to make scientific prevention. The second countermeasure is to strictly manage the construction site and eliminate safety hazards. A domestic statistical report showed that about 25% of fires involving building insulation materials occur during the stacking of insulation materials, 65% occur during the laying of insulation materials, and less than 10% occur during the use of buildings. It can be seen that the construction process of building wall insulation is a high-risk period for fire accidents. Regulatory authorities shall strengthen the standardized management of the manufacturers, construction enterprises and markets of building external wall insulation material, carry out the certification of wall insulation systems, and introduce licenses, insurance and other systems to improve the safety of building wall insulation. When carrying out fire supervision and inspection, the fire department shall transmit the awareness of fire prevention to the management personnel at the construction site, and also require that each working face shall be ensured to have a fire water supply at the construction site, so as to carry out self-rescue in case of fire. Only strict construction site management can eliminate fire safety hazards to the maximum extent. The third countermeasure is to update and improve various types of firefighting and rescue equipment, and enhance the ability to tackle difficulties. At present, the speed of fire equipment “growing taller” in China is far from keeping up with the speed of building “growing taller”.